She has an eagle-like face and has blue eyes. She looks to be in her mid-twenties, but could be older due to the One Power.
Strength in the One Power
Viendre is among the strongest female channelers. Her level is described as such:
—Winter's Heart, Prologue
But in the "Wheel of Time Companion" there is a mistake about her strength, in fact only Tamela is confirmed stronger 5(+8) than Elayne 8(+5); instead Viendre is described even some levels below Elayne, at level 10(+3). Even if at the time of her meeting with Viendre Elayne had not reached her full potential, she was near it, so two levels below is still too much to describe Viendre as stronger.